You could just change the visibility of the primary collection to be hidden via an impossible condition or only be visible to certain users. If a user does try to navigate back to that main tab, they just won’t see anything since the collection is hidden. You could leave it as a blank tab, or have a message saying “nothing to see here”.
But I have also seen that you found the other post referring to the url query parameter method, which works quite well, but requires a little bit more setup.